자기자신을 제외한 모든 배열 요소의 곱 리턴

Author: holmir97

ProductOfArrayExceptSelf.java

@@ -0,0 +1,55 @@
+public class ProductOfArrayExceptSelf {
+
+    // my solution _ O(n)
+    public int[] productExceptSelf1(int[] nums) {
+        int tmp = 1;
+        int cnt = 0;
+        boolean zeroFlag = false;
+
+        for (int i = 0; i < nums.length; i++) {
+            if(nums[i] == 0) {
+                cnt++;
+                if(cnt == 1 )
+                    continue;
+            }
+            tmp *= nums[i];
+        }
+
+        if(cnt != 1)
+            zeroFlag = true;
+
+        if(zeroFlag) {
+            for (int i = 0; i < nums.length; i++) {
+                if (nums[i] == 0)
+                    nums[i] = tmp;
+                else
+                    nums[i] = tmp / nums[i];
+            }
+        }else {
+            for (int i = 0; i < nums.length; i++) {
+                if (nums[i] == 0)
+                    nums[i] = tmp;
+                else
+                    nums[i] = 0;
+            }
+        }
+        return nums;
+    }
+
+
+    // my solution _ O(n^2) _ Time Limit Exceeded
+    public int[] productExceptSelf2(int[] nums) {
+        int[] answer = new int[nums.length];
+        for (int i = 0; i < answer.length; i++)
+            answer[i] = 1;
+
+        for (int i = 0; i < nums.length; i++) {
+            for (int j = 0; j < nums.length; j++) {
+                if (i == j)
+                    continue;
+                answer[i] *= nums[j];
+            }
+        }
+        return answer;
+    }
+}